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Joel M H Teichman

Publications and source records attributed to Joel M H Teichman.

16 recordsLinked to original sources
PubMed2006

Urinary calculus fragmentation during Ho: YAG and Er:YAG lithotripsy.

BACKGROUND AND OBJECTIVES: We tested Ho:YAG and Er:YAG laser ablation of human urinary calculi to determine if Er:YAG is a more efficient lithotripsy device. STUDY DESIGN/MATERIALS AND METHODS: Ablation efficiency of Ho:YAG and Er:YAG lasers was tested at varying energy settings, ranging from the damage threshold to clinical energy setting associated with Ho:YAG laser. Stones of known composition (calcium oxalate monohydrate (COM), cystine, and uric acid (UA)) were irradiated. Crater width, depth, and ablation volumes were determined using an optical coherence tomography (OCT). RESULTS: For all stones and energy settings, the Er:YAG laser produced deeper craters and larger ablation volumes than Ho:YAG laser. The Ho:YAG laser created wider craters during the multiple pulse process and the shape of craters was irregular. CONCLUSIONS: The Er:YAG laser is more efficient than the Ho:YAG laser for lithotripsy. The deeper craters produced by the Er:YAG laser is attributed to the high absorption of energy at its wavelength.

Erbium↗
PubMed2006

Dependence of calculus retropulsion on pulse duration during Ho: YAG laser lithotripsy.

BACKGROUND AND OBJECTIVES: The purpose of this study was to investigate the effect of optical pulse duration on stone retropulsion during Ho:YAG (lambda = 2.12 microm) laser lithotripsy. STUDY DESIGN/MATERIALS AND METHODS: A clinical Ho:YAG laser with pulse durations was employed to fragment calculus phantoms and to evaluate stone phantom retropulsion. At a given pulse energy, optical pulse durations were divided into two discrete conditions: short pulse (tau(p): 120 to approximately 190 microseconds at FWHM) and long pulse (tau(p): 210 to approximately 350 microseconds at FWHM). Plaster of Paris calculus phantoms were ablated at different energy levels using optical fibers of varying diameters (273, 365, and 550 microm in core size). The dynamics of the recoil action of a calculus phantom was monitored using a high-speed camera; the laser-induced craters were evaluated with optical coherent tomography (OCT). Bubble formation and collapse were recorded with a fast flash photography setup, and acoustic transients were measured with a hydrophone. RESULTS: Shorter pulse durations produced more stone retropulsion than longer pulses at any given pulse energy. Regardless of pulse duration, higher pulse energy and larger fibers resulted in larger ablation volume and retropulsion (P<0.05). For shorter pulse durations, more rapid bubble expansion was observed and higher amplitudes of the collapse pressure wave were measured (P<0.05). CONCLUSION: Less retropulsion and equivalent fragmentation occurred when Ho:YAG pulse duration increased.

Analysis of Variance↗
PubMed2005

How do residents manage personal finances?

BACKGROUND: We examined three research questions: How do residents' debts and savings compare to the general public? How do surgical residents' financial choices compare to other residents? How may institutions help residents' personal financial decisions? METHODS: The Survey of Consumer Finances was modified and piloted tested to elicit financial information. The instrument was completed by 612 residents at 8 programs. RESULTS: Only 60% of residents budgeted expenses, and 25% and 10% maintained cash balances <611 dollars and unpaid credit card balances >10,000 dollars, respectively. Compared with controls, residents held greater median ratios of debt to household income (2.46 vs. 1.06, P <0.0001), fewer assets to income (0.64 vs. 2.28, P <0.0001), less net wealth to income -1.43 vs. 0.90, P <0.0001), and lower retirement savings balance to household income (0.01 vs. 0.12, P <0.0001). Surgery residents were the least financially conservative group. Mean annual resident contributions to retirement accounts were $1532 higher at institutions with versus without retirement plans (P <0.01). CONCLUSIONS: Resident debts are higher and savings lower than the general public. This behavior is most common among surgery residents. Residents save more for retirement when they are eligible for tax-deferred retirement plans. Graduate medical programs should instruct residents on financial management.

Adult↗
PubMed2005

What is the value of cystoscopy with hydrodistension for interstitial cystitis?

OBJECTIVES: To determine the utility of cystoscopy with hydrodistension for the diagnosis and therapy of interstitial cystitis. Cystoscopy with hydrodistension is the most commonly performed diagnostic test and procedure in patients with interstitial cystitis. METHODS: Eighty-four consecutive patients with interstitial cystitis (68 women and 16 men) were studied retrospectively. The patients underwent history and physical examination, urinalysis, and urine culture and filled in a voiding diary and pain urgency frequency questionnaire. Cystoscopy with hydrodistension was performed in 47 patients. Patients who had and had not undergone hydrodistension were compared. Patients who underwent hydrodistension were characterized and followed up for response. RESULTS: The mean patient age was 41 years, mean daily voided volume was 98 mL, mean number of nocturnal episodes was 3, and pain urgency frequency score was 21. Comparing patients undergoing versus not undergoing hydrodistension, pain was reported in 61% versus 25% (P = 0.03), vaginal pain in 62% versus 32% (P = 0.02), and dyspareunia or ejaculatory pain in 67% versus 29% (P < 0.01), respectively. All other parameters were statistically similar. Of the patients undergoing hydrodistension, 43 had follow-up and 24 (56%) reported improvement (mean duration of 2 months). Of the patients with and without improvement, no difference was found in mean age (40 versus 46 years, P = 0.20), duration of symptoms (7 versus 7 years, P = 0.92), anesthetic capacity (722 versus 721 mL, P = 0.99), or glomerulation grade (P = 0.61), respectively. CONCLUSIONS: Cystoscopy with hydrodistension provided little useful information above and beyond the history and physical examination findings. As therapy, 56% of patients reported improvement, but the duration was short lived.

Adolescent↗
PubMed2005

Prevalence, diagnosis, characterization, and treatment of prostatitis, interstitial cystitis, and epididymitis in outpatient urological practice: the Canadian PIE Study.

OBJECTIVES: To determine the prevalence, diagnostic patterns, and management of prostatitis, interstitial cystitis, and epididymitis (PIE) in Canadian urology outpatient practice. METHODS: Representative urologists were randomly selected from the Canadian and Quebec Urological Associations. Each patient identified with a PIE diagnosis during a typical 2-consecutive-week period during April 2004 to July 2004 was requested to complete a corresponding Chronic Prostatitis Symptom Index (CPSI), O'Leary-Sant Symptom Index (OSSI), or a Chronic Epididymitis Symptom Index (CESI). Each day the participant urologist completed an outpatient log and a detailed programmed chart review to transcribe demographics, investigations, and treatments associated with each PIE patient. RESULTS: Sixty-five urologists were invited to participate. Fifty-seven (88%) agreed, and 48 (74%) completed the audit. Of the 8712 patients seen in outpatient practice (average 182 per urologist), 2675 were female and 6037 male. Prostatitis was identified in 2.7% of the men (n = 166; mean age 50 years; mean duration 3.1 years; mean CPSI score 19.7), interstitial cystitis in 2.8% of patients (n = 242; 211 women [7.9%], 26 men [0.4%]; mean age 50.2 years, mean duration 4.5 years, mean OSSI score 11.8), and epididymitis in 0.9% of men (n = 57; mean age 41.1 years, mean duration 2.5 years, mean CESI score 15.5). There was wide variance in investigations and treatments. CONCLUSIONS: This prospective audit indicates that prostatitis might not be as common as frequently believed and that interstitial cystitis is more common, and it represents the first estimate of the prevalence of epididymitis in urologic practice. The wide variance in investigations and treatments confirms the need for practice management guidelines.

Adolescent↗
PubMed2005

Performance and safety of holmium: YAG laser optical fibers.

BACKGROUND AND PURPOSE: Lower-pole ureteronephroscopy requires transmission of holmium:YAG energy along a deflected fiber. Current ureteroscopes are capable of high degrees of deflection, which may stress laser fibers beyond safe limits during lower-pole use. We hypothesized that optical fiber and safety measures differ among manufacturers. MATERIALS AND METHODS: Small (200-273-microm) and medium-diameter (300-400-microm) Ho:YAG fibers were tested in a straight and 180 degrees bent configuration. Energy transmission was measured by an energy detector. Fiber durability was assessed by firing the laser in sequentially tighter bending diameters. The fibers were bent to 180 degrees with a diameter of 6 cm and run at 200- to 4000-mJ pulse energy to determine the minimum energy required to fracture the fiber. The bending diameter was decreased by 1-cm increments and testing repeated until a bending diameter of 1 cm was reached. The maximum deflection of the ACMI DUR-8E ureteroscope with each fiber in the working channel was recorded. The flow rate through the working channel of the DUR-8E was measured for each fiber. RESULTS: The mean energy transmission differed among fibers (P < 0.001). The Lumenis SL 200 and the InnovaQuartz 400 were the best small and medium-diameter fibers, respectively, in resisting thermal breakdown (P < 0.01). The Dornier Lightguide Super 200 fractured repeatedly at a bend diameter of 2 cm and with the lowest energy (200 mJ). The other small fibers fractured only at a bend diameter of 1 cm. The Sharplan 200 and InnovaQuartz Sureflex 273T were the most flexible fibers, the Lumenis SL 365 the least. The flow rate was inversely proportional to four times the power of the diameter of the fiber. CONCLUSIONS: Optical performance and safety differ among fibers. Fibers transmit various amounts of energy to their cladding when bent. During lower-pole nephroscopy with the fiber deflected, there is a risk of fiber fracture from thermal breakdown and laser-energy transmission to the endoscope. Some available laser fibers carry a risk of ureteroscope damage.

Aluminum↗
PubMed2005

Personal finances of residents at three Canadian universities.

OBJECTIVES: To address 3 research questions (What financial choices do residents make? Are the financial choices of residents similar to those of the general public? Are the financial choices of surgical residents reasonable?), we examined financial data from Canadian residents. METHODS: A written survey was administered to 338 residents (103 of them surgical residents) at 3 Canadian training institutions (University of Toronto, Queen's University and University of Manitoba). Resident household cash flows, assets and liabilities were characterized. Finances for residents were compared with those of the general public, by means of the Survey of Household Spending and Survey of Financial Security. RESULTS: Median resident income was 45,000 dollars annually (Can dollars throughout). With a working spouse, median household income was 87,500 dollars. Among residents, 62% had educational debt (median 37,500 dollars), 39% maintained unpaid credit-card balances (median 1750 dollars), 36% did not budget expenses, 25% maintained cash reserves <275 dollars, and 22% contributed neither to retirement nor nonretirement investments. Residents spent more on vehicles compared with members of the general public (median 17,500 dollars v. 10,720 dollars, p = 0.002) and on monthly housing (median 875 dollars v. 729 dollars, p < 0.001), respectively. Residents were more likely to carry student loans than people in the general population (61% v. 21%), more likely to carry vehicle loans (74% v. 29%) and less likely to carry credit-card debts (39% v. 50%, respectively). Surgical residents had income expectations after graduation higher than current billings justified. Fewer surgical (69%) than anesthesiology residents (88%, p < 0.05) contributed to Registered Retirement Savings Plans. CONCLUSIONS: From this limited sample, residents spend more than age- and income-matched members of the general public. Many residents save too little, fail to budget, and carry high educational and credit-card debts. Surgical residents' expectations of future income may be unrealistic. Further study is warranted.

Adult↗
PubMed2004

Review of laser fibers: a practical guide for urologists.

Holmium:YAG lithotripsy requires transmission of optical energy using laser fibers. Optical fibers may be subjected to severe angular deflection and bending during flexible nephroscopy or flexible ureteronephroscopy. Irradiation of a deflected fiber in a tight bending radius may produce fiber failure and consequent irradiation of the ureteroscope, with risk of instrument damage and patient injury. We review the physics and engineering aspects of optical fibers to explain why fibers fail.

Equipment Failure↗
PubMed2004

Dependence of calculus retropulsion dynamics on fiber size and radiant exposure during Ho:YAG lithotripsy.

During pulsed laser lithotripsy, the calculus is subject to a strong recoil momentum which moves the calculus away from laser delivery and prolongs the operation. This study was designed to quantify the recoil momentum during Ho:YAG laser lithotripsy. The correlation among crater shape, debris trajectory, laser-induced bubble and recoil momentum was investigated. Calculus phantoms made from plaster of Paris were ablated with free running Ho:YAG lasers. The dynamics of recoil action of a calculus phantom was monitored by a high-speed video camera and the laser ablation craters were examined with Optical Coherent Tomography (OCT). Higher radiant exposure resulted in larger ablation volume (mass) which increased the recoil momentum. Smaller fibers produced narrow craters with a steep contoured geometry and decreased recoil momentum compared to larger fibers. In the presence of water, recoil motion of the phantom deviated from that of phantom in air. Under certain conditions, we observed the phantom rocking towards the fiber after the laser pulse. The shape of the crater is one of the major contributing factors to the diminished recoil momentum of smaller fibers. The re-entrance flow of water induced by the bubble collapse is considered to be the cause of the rocking of the phantom.

Calculi↗
PubMed2003

Long-term results for Malone antegrade continence enema for adults with neurogenic bowel disease.

OBJECTIVES: To determine the long-term outcomes from the Malone antegrade continence enema (ACE) procedure in adult neurogenic patients. METHODS: A retrospective review of adult patients who underwent the ACE procedure for neurogenic bowel was done. Patients were studied if they had follow-up of greater than 4 years. We compared pre-ACE and post-ACE toileting times, bowel continence status, and complications, and elicited patient subjective satisfaction with their quality of life. RESULTS: Six patients were available for study. Mean age was 35 years with a mean follow-up of 4.5 years. Urinary diversion was done in 5 patients. Pre-ACE toileting time was 190 +/- 45 minutes versus post-ACE toileting time of 28 +/- 20 minutes (P <0.001). Four of six patients pre-ACE were incontinent of stool per rectum compared with 1 of these 4 patients post-ACE (P = 0.03). Five patients were continent of stool per ACE stoma. Four patients (67%) had complications. Three of five patients (60%) who underwent synchronous urinary diversion required postoperative re-exploration. Five patients (83%) were satisfied with their outcome and rated their quality of life higher after the ACE procedure compared with pre-ACE. CONCLUSIONS: The ACE procedure is effective in the long-term management of adult neurogenic bowel. The complication and re-exploration rates are high. Patients must be properly selected to determine appropriate motivation.

Adult↗
PubMed2003

Effect of lithotripsy on holmium:YAG optical beam profile.

PURPOSE: To determine the effect of holmium:YAG lithotripsy on the optical beam profile. MATERIALS AND METHODS: Beam profiles of the laser light from holmium:YAG optical fiber systems were characterized with a pyroelectric camera. Beam profiles were measured with 272-microm and 365-microm optical fibers both straight and bent to simulate lower-pole ureteronephroscopy. Struvite calculi were irradiated. Beam profiles and energy outputs were characterized for the fibers before and after ablation. Ablation crater geometry was characterized with optical coherence tomography. RESULTS: Undamaged, straight fibers produced a near-Gaussian beam profile. Craters showed a similar near-Gaussian shape. Undamaged, bent 272-microm fibers produced a near-Gaussian beam but slightly flatter profile than the straight fiber. The bent 272-microm fiber transmitted 99% to 100% of the energy, similar to the 100% transmission of the straight fibers. After ablation, measured energy output dropped by 30% within 50 pulses at 0.2 J pulse energy. The damaged fibers produced irregular beam profiles with hot spots. Craters showed irregular contours. CONCLUSIONS: During Ho:YAG lithotripsy, the beam profile at the optical fiber tip approaches a Gaussian distribution. This shape corresponds to the crater produced on the stone surface. With further ablation, the beam profile becomes erratic and unpredictable, with loss of lithotripsy efficiency. The findings provide further insight into the photothermal mechanism of Ho:YAG lithotripsy.

Humans↗
PubMed2003

Stone retropulsion during holmium:YAG lithotripsy.

PURPOSE: We modeled retropulsion during holmium:YAG lithotripsy on the conservation of momentum, whereby the force of ejected fragment debris off of the calculous surface should equal the force of retropulsion displacing the stone. We tested the hypothesis that retropulsion occurs as a result of ejected stone debris. MATERIALS AND METHODS: Uniform calculous phantoms were irradiated with holmium:YAG energy in air and in water. Optical fiber diameter and pulse energy were varied. Motion of the phantom was monitored with high speed video imaging. Laser induced crater volume and geometry were characterized by optical coherence tomography. To determine the direction of plume laser burn paper was irradiated at various incident angles. RESULTS: Retropulsion was greater for phantoms irradiated in air versus water. Retropulsion increased as fiber diameter increased and as pulse energy increased (p <0.001). Crater volumes increased as pulse energy increased (p <0.05) and generally increased as fiber diameter increased. Crater geometry was wide and shallow for larger fibers, and narrow and deeper for smaller fibers. The ejected plume propagated in the direction normal to the burn paper surface regardless of the laser incident angle. CONCLUSIONS: Retropulsion increases as pulse energy and optical fiber diameter increase. Vector analysis of the ejected plume and crater geometry explains increased retropulsion using larger optical fibers. Holmium:YAG lithotripsy should be performed with small optical fibers to limit retropulsion.

Biomechanical Phenomena↗
PubMed2002

Erbium: YAG laser lithotripsy mechanism.

PURPOSE: We tested the hypothesis that the mechanism of long pulse erbium:YAG laser lithotripsy is photothermal. MATERIALS AND METHODS: Human urinary calculi were placed in deionized water and irradiated with erbium:YAG laser energy delivered through a sapphire optical fiber. Erbium:YAG bubble dynamics were visualized with Schlieren flash photography and correlated to acoustic emissions measured by a polyvinylidene fluoride needle hydrophone. The sapphire fiber was placed either parallel or perpendicular to the calculus surface to assess the contribution of acoustic transients to fragmentation. Stones were irradiated using desiccated stone irradiated in air, hydrated stone irradiated in air and hydrated stone irradiated in water. Ablation crater sizes were compared. Uric acid stones were irradiated in water and the water was assayed for cyanide. RESULTS: During the early phase of vapor bubble expansion, acoustic transients had minimal effects on calculus fragmentation. Fragmentation occurred due to direct absorption of laser energy transmitted to the calculus through the vapor channel between the sapphire fiber tip and calculus. The forward axial expansion of the bubble occurred more rapidly than the radial expansion. A parallel oriented fiber on the calculus surface produced no fragmentation but generated larger amplitude acoustic transients compared to perpendicular orientation. In perpendicular orientation the erbium:YAG laser did not generate any collapse acoustic waves but fragmentation occurred. Crater width was greatest for desiccated stones irradiated in air (p <0.03). Cyanide production increased as erbium:YAG irradiation of uric acid calculi increased, (r2 = 0.98). CONCLUSIONS: The erbium:YAG laser fragments stones through a photothermal mechanism.

Humans↗
PubMed2002

Laser lithotripsy.

PURPOSE OF REVIEW: All literature related to laser lithotripsy published within the past year was reviewed. Salient articles have been reviewed and grouped according to safety issues, efficacy, comparison studies, biliary applications or future directions. RECENT FINDINGS: There is no evidence of renal deterioration after holmium:yttrium-aluminium-garnet lithotripsy. Laser-related complications occur in less than 1%. Stone-free rates from holmium:yttrium-aluminium-garnet lithotripsy are greater than 90% for ureteral calculi, and 67-84% for renal calculi. This method of lithotripsy is effective for ureteral and renal calculi in morbidly obese patients who are not suitable candidates for shock-wave lithotripsy or percutaneous nephrolithotomy. Holmium:yttrium-aluminium-garnet lithotripsy is more effective than pneumatic lithotripsy for ureteral calculi, but no more effective than shock-wave lithotripsy (Dornier HM-3) for distal ureteral calculi. Holmium:yttrium-aluminium-garnet lithotripsy of biliary calculi is uniformly effective. Preliminary data showed the erbium:yttrium-aluminium-garnet laser to be more efficient than holmium:yttrium-aluminium-garnet energy, but current erbium:yttrium-aluminium-garnet fibers are impractical. SUMMARY: The holmium:yttrium-aluminium-garnet laser is safe and effective. It is the lithotrite of choice for endoscopic ureteral and ureterorenoscopic lithotripsy.

Glomerular Filtration Rate↗